Liquid discharge device and UV irradiator

Abstract

To suppress a load that is applied to a motor for moving a carriage.SOLUTION: A liquid discharge device comprises: a liquid discharge unit for discharging onto a medium a liquid that is cured by UV irradiation; an irradiation unit for radiating UV light to the liquid discharged onto a medium; a carriage which carries the liquid discharge unit and the irradiation unit, and moves on the medium; and a motor for moving the carriage. The irradiation unit comprises a substrate, and a UV light source provided on the substrate to emit UV light. The substrate includes a base material made of aluminum.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device and an ultraviolet irradiation device. [Background technology]

[0002] There is known a liquid ejection device that ejects ultraviolet curable ink (an example of a "liquid") onto a medium that is cured by irradiation with ultraviolet rays. For example, Patent Document 1 discloses a liquid ejection device that includes a liquid ejection unit that ejects ultraviolet curable ink onto a medium, an irradiation unit that irradiates the liquid ejected onto the medium with ultraviolet rays, a carriage that carries the liquid ejection unit and the irradiation unit and moves above the medium, and a motor for moving the carriage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-017731 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the conventional technology, since the irradiation unit is mounted on the carriage in addition to the liquid ejection unit, there is a problem in that the load on the motor for moving the carriage increases. [Means for solving the problem]

[0005] In order to solve the above problems, the liquid ejection device of the present invention comprises a liquid ejection unit that ejects a liquid that hardens when irradiated with ultraviolet light onto a medium, an irradiation unit that irradiates the liquid ejected onto the medium with ultraviolet light, a carriage that carries the liquid ejection unit and the irradiation unit and moves over the medium, and a motor for moving the carriage, wherein the irradiation unit comprises a substrate and an ultraviolet light source that is provided on the substrate and emits ultraviolet light, and the substrate has an aluminum base material.

[0006] Furthermore, the ultraviolet irradiation device according to the present invention is provided in a liquid ejection device that includes a liquid ejection unit that ejects a liquid onto a medium that hardens when irradiated with ultraviolet light, a carriage that carries the liquid ejection unit and moves over the medium, and a motor for moving the carriage, and is mounted on the carriage and irradiates ultraviolet light onto the liquid ejected onto the medium, characterized in that it includes a substrate and an ultraviolet light source that is mounted on the substrate and emits ultraviolet light, and the substrate has an aluminum base material. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram showing an example of the configuration of an inkjet printer 1 according to a first embodiment of the invention. [Figure 2] FIG. 1 is a perspective view showing an example of a schematic internal structure of an inkjet printer 1. [Figure 3] FIG. 10 is a cross-sectional view illustrating an example of the structure of a discharge section D[m]. [Figure 4] FIG. 2 is a plan view showing an example of the arrangement of objects mounted on the carriage 110. [Figure 5] FIG. 2 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiation unit 5. [Figure 6] 2 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiation unit 5 and an ultraviolet light source E. FIG. [Figure 7] FIG. 2 is a block diagram showing an example of the configuration of a temperature detection integrated circuit 7. [Figure 8]10 is an explanatory diagram showing an example of the radiant flux characteristics of an ultraviolet light source E. FIG. [Figure 9] FIG. 1 is a diagram illustrating the premise of an illuminance simulation. [Figure 10] FIG. 10 is a diagram showing the results of a first illuminance simulation. [Figure 11] FIG. 1 is an explanatory diagram showing an overview of a conventional example. [Figure 12] FIG. 1 is a diagram showing the thermal conductivity and specific gravity of various metals. [Figure 13] FIG. 10 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiation unit 5B according to a second embodiment of the present invention. [Figure 14] FIG. 1 is a diagram illustrating the premise of an illuminance simulation. [Figure 15] FIG. 10 is a diagram showing the results of a second illuminance simulation. [Figure 16] FIG. 10 is a diagram showing the results of a third illuminance simulation. [Figure 17] FIG. 10 is a diagram showing the results of a fourth illuminance simulation. [Figure 18] FIG. 10 is a diagram showing the results of a fifth illuminance simulation. [Figure 19] FIG. 10 is a diagram showing the results of a sixth illuminance simulation. [Figure 20] FIG. 12 is a diagram showing the results of a seventh illuminance simulation. [Figure 21] FIG. 13 is a diagram showing the results of an eighth illuminance simulation. [Figure 22] FIG. 10 is a diagram showing the results of the second to eighth illuminance simulations. [Figure 23] FIG. 10 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiation unit 5C according to a third embodiment of the present invention. [Figure 24] FIG. 1 is a diagram illustrating the premise of an illuminance simulation. [Figure 25] FIG. 13 is a diagram showing the results of a ninth illuminance simulation. [Figure 26] FIG. 17 is a diagram showing the results of the tenth illuminance simulation. [Figure 27]It is a cross-sectional view showing an example of the configuration of the ultraviolet light source E according to Modification 1 of the present invention. [Figure 28] It is a cross-sectional view showing an example of the directivity characteristics of the ultraviolet light source E.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part are appropriately different from the actual ones. In addition, the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are imposed. However, the scope of the present invention is not limited to these embodiments unless there is a description to specifically limit the present invention in the following description.

[0009] <<A.First Embodiment>> In the first embodiment, an inkjet printer 1 that discharges ink to form an image on a recording paper PP will be exemplified to explain the liquid discharge device.

[0010] <<A.1. Outline of Inkjet Printer>> Hereinafter, an example of the configuration of the inkjet printer 1 according to the first embodiment will be described while referring to FIGS. 1 to 4.

[0011] FIG. 1 is a functional block diagram showing an example of the configuration of the inkjet printer 1.

[0012] As shown in FIG. 1, print data Img indicating an image to be formed by the inkjet printer 1 is supplied to the inkjet printer 1 from a host computer such as a personal computer or a digital camera. The inkjet printer 1 executes a printing process to form an image indicated by the print data Img supplied from the host computer on the recording paper PP.

[0013] As shown in Figure 1, the inkjet printer 1 includes a control unit 2 that controls each part of the inkjet printer 1, a liquid ejection unit 3 provided with an ejection section D that ejects ink onto recording paper PP, a drive signal generation unit 4 that generates a drive signal Com for driving the ejection section D, an ultraviolet irradiation unit 5 that irradiates ultraviolet light onto the ink ejected onto the recording paper PP, and a transport unit 9 that transports the liquid ejection unit 3 and the recording paper PP. In the first embodiment, it is assumed that the ink ejected from the liquid ejection unit 3 is ultraviolet curable ink that is cured by irradiation with ultraviolet rays. In the first embodiment, the inkjet printer 1 is an example of a "liquid ejection device," the ultraviolet curable ink is an example of a "liquid," the recording paper PP is an example of a "medium," and the ultraviolet irradiation unit 5 is an example of an "irradiation unit" and an "ultraviolet irradiation device."

[0014] In the first embodiment, it is assumed that the inkjet printer 1 includes one or more liquid ejection units 3 and one or more drive signal generation units 4 that correspond one-to-one to the one or more liquid ejection units 3. Specifically, in the first embodiment, it is assumed that the inkjet printer 1 includes four liquid ejection units 3 and four drive signal generation units 4 that correspond one-to-one to the four liquid ejection units 3. However, for ease of explanation, the following description may focus on one of the four liquid ejection units 3 and one of the four drive signal generation units 4 that is provided to correspond to one of the liquid ejection units 3, as shown in FIG.

[0015] The control unit 2 is configured to include one or more central processing units (CPUs). However, the control unit 2 may include a programmable logic device such as a field-programmable gate array (FPGA) instead of or in addition to a CPU. The control unit 2 also includes a memory. The memory is configured to include one or both of a volatile memory such as a random access memory (RAM) and a non-volatile memory such as a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a programmable ROM (PROM).

[0016] The control unit 2 generates signals for controlling the operation of each part of the inkjet printer 1, such as a specification signal SI, a waveform specification signal dCom, a light source control signal SL, a carriage transport control signal SK, and a medium transport control signal SB.

[0017] Here, the waveform specification signal dCom is a digital signal that defines the waveform of the drive signal Com. The drive signal Com is an analog signal for driving the discharge section D. The specification signal SI is a digital signal that specifies the type of operation of the discharge section D. Specifically, the specification signal SI specifies whether or not to supply the drive signal Com to the discharge section D, thereby specifying the type of operation of the discharge section D, such as whether or not to discharge ink from the discharge section D. The light source control signal SL is a signal for controlling the ultraviolet irradiation unit 5. The carriage transport control signal SK and the medium transport control signal SB are signals for controlling the transport unit 9.

[0018] When a printing process is performed, the control unit 2 generates signals, such as a designation signal SI, for controlling the liquid ejection unit 3 based on the print data Img. Furthermore, when a printing process is performed, the control unit 2 generates signals, such as a waveform designation signal dCom, for controlling the drive signal generation unit 4. Furthermore, when a printing process is performed, the control unit 2 generates signals, such as a carriage transport control signal SK and a medium transport control signal SB, for controlling the transport unit 9. In this way, during the printing process, the control unit 2 controls the transport unit 9 to move the liquid ejection unit 3 and the recording paper PP, while also adjusting the presence or absence of ink ejection from the ejection section D, the timing of ink ejection, and the like, and controls each part of the inkjet printer 1 so that an image corresponding to the print data Img is formed on the recording paper PP.

[0019] As shown in FIG. 1, the liquid ejection unit 3 includes a supply circuit 31 and a liquid ejection head 32.

[0020] The liquid ejection head 32 has M ejection units D. Here, the value M is a natural number that satisfies "M≧1." Note that, hereinafter, the mth ejection unit D of the M ejection units D provided in the liquid ejection head 32 may be referred to as ejection unit D[m]. Here, the variable m is a natural number that satisfies "1≦m≦M." Furthermore, hereinafter, when a component or signal of the inkjet printer 1 corresponds to a ejection unit D[m] among the M ejection units D, the subscript [m] may be added to the symbol representing the component or signal. The supply circuit 31 switches whether to supply the drive signal Com to the discharge section D[m] based on the designation signal SI. Hereinafter, the drive signal Com supplied to the discharge section D[m] may be referred to as the supply drive signal Vin[m].

[0021] As shown in FIG. 1, the ultraviolet irradiation unit 5 includes an ultraviolet light source module 6 and a temperature detection integrated circuit 7.

[0022] The ultraviolet light source module 6 includes a plurality of ultraviolet light sources E that emit ultraviolet light, and irradiates the recording paper PP that is being transported by the transport unit 9 with ultraviolet light.

[0023] In the first embodiment, it is assumed that the ultraviolet light emitted from the ultraviolet light source E has a wavelength of 250 nm or more and 410 nm or less. Therefore, compared to an embodiment in which ultraviolet light having a wavelength of 100 nm or more and 230 nm or less is emitted from the ultraviolet light source E, it is possible to reduce the possibility that the ultraviolet light emitted from the ultraviolet light source E will react with oxygen in the air to generate ozone. Although not shown in the drawings, the inkjet printer 1 according to the first embodiment is provided with rubber parts (an example of a "specific component"). Rubber parts deteriorate when exposed to ozone. However, in the first embodiment, as described above, the ultraviolet light source E emits ultraviolet light having a wavelength of 250 nm or more and 410 nm or less, which makes it possible to suppress deterioration of the rubber parts compared to an embodiment in which the ultraviolet light source E emits ultraviolet light having a wavelength of 100 nm or more and 230 nm or less.

[0024] The temperature detection integrated circuit 7 detects the temperature inside the ultraviolet irradiation unit 5 and outputs a temperature detection signal DT, which is a digital signal indicating a value based on the detected temperature. The control unit 2 generates a light source control signal SL based on the temperature detection signal DT output by the temperature detection integrated circuit 7.

[0025] In the first embodiment, the light source control signal SL is a signal that specifies the intensity of ultraviolet light emitted from the ultraviolet light source E. More specifically, in the first embodiment, the ultraviolet light source module 6 causes each ultraviolet light source E to emit ultraviolet light according to the intensity indicated by the light source control signal SL. However, the present invention is not limited to this aspect. The light source control signal SL may also be a signal that specifies the on / off of the ultraviolet light source E. In this case, the ultraviolet light source module 6 turns on the ultraviolet light source E when the light source control signal SL specifies on, and turns off the ultraviolet light source E when the light source control signal SL specifies off.

[0026] As shown in FIG. 1, the transport unit 9 includes a carriage transport motor 91 and a medium transport motor 92.

[0027] The carriage transport motor 91 transports a carriage 110, which will be described later, based on a carriage transport control signal SK. The medium transport motor 92 transports the recording paper PP based on the medium transport control signal SB.

[0028] FIG. 2 is a perspective view showing an example of the general internal structure of the inkjet printer 1. As shown in FIG.

[0029] 2, the first embodiment assumes that the inkjet printer 1 is a serial printer. Specifically, when performing a printing process, the inkjet printer 1 transports the recording paper PP in the X1 direction while moving the liquid ejection unit 3 in the Y1 direction, which intersects the X1 direction, and forms an image on the recording paper PP according to the print data Img by ejecting ink from the liquid ejection unit 3. When performing a printing process, the inkjet printer 1 also moves the ultraviolet irradiation unit 5 in the Y1 direction and irradiates the recording paper PP with ultraviolet light from the ultraviolet irradiation unit 5, thereby curing the ink ejected onto the recording paper PP. In the first embodiment, when the inkjet printer 1 moves the liquid ejection unit 3 to the end in the Y1 direction, it moves the liquid ejection unit 3 in the Y2 direction, which is opposite to the Y1 direction, without ejecting ink from the liquid ejection unit 3. Also, in the first embodiment, the inkjet printer 1 moves the ultraviolet irradiation unit 5 in the Y2 direction without emitting ultraviolet light from the ultraviolet irradiation unit 5.

[0030] Hereinafter, the X1 direction and its opposite X2 direction will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and its opposite Y2 direction will be collectively referred to as the "Y-axis direction," and the Z1 direction intersecting the X-axis and Y-axis directions and its opposite Z2 direction will be collectively referred to as the "Z-axis direction." In the first embodiment, as an example, a description will be given assuming that the X-axis, Y-axis, and Z-axis directions are perpendicular to one another. However, the present invention is not limited to this aspect. The X-axis, Y-axis, and Z-axis directions may intersect one another. In the first embodiment, the Z1 direction is the direction in which ink is ejected from the ejection section D.

[0031] 2, the inkjet printer 1 according to the first embodiment includes a housing 100 and a carriage 110 that can move back and forth in the Y-axis direction within the housing 100. The carriage 110 carries four liquid ejection units 3 and an ultraviolet irradiation unit 5. Specifically, the carriage 110 carries the four liquid ejection units 3 and the ultraviolet irradiation unit 5 so that the four liquid ejection units 3 are positioned in the Y1 direction when viewed from the ultraviolet irradiation unit 5.

[0032] In the first embodiment, as shown in FIG. 2, it is assumed that the carriage 110 is equipped with four ink cartridges 120, each corresponding to one of the four colors of ink: cyan, magenta, yellow, and black. Furthermore, in the first embodiment, it is assumed that the carriage 110 is equipped with four liquid ejection units 3, each corresponding to one of the four ink cartridges 120, as described above. Each ejection section D[m] receives a supply of ink from the ink cartridge 120 corresponding to the liquid ejection unit 3 in which the ejection section D[m] is provided. This allows each ejection section D[m] to be filled with the supplied ink, and to eject the ink filled inside the ejection section D[m] from the nozzle N provided in the ejection section D[m]. The ink cartridges 120 may be provided outside the carriage 110.

[0033] As described above, the inkjet printer 1 according to the first embodiment also includes a transport unit 9. As shown in Fig. 2, the transport unit 9 includes a carriage transport motor 91 for reciprocating the carriage 110 in the Y axis direction, a carriage guide shaft 96 that supports the carriage 110 so that it can reciprocate in the Y axis direction, a belt 97 that transports the carriage 110 in the Y axis direction based on the drive of the carriage transport motor 91, a medium transport motor 92 for transporting the recording paper PP in the X1 direction, a medium transport mechanism 93 that rotates based on the drive of the medium transport motor 92 to transport the recording paper PP in the X1 direction, and a platen 95 provided on the Z1 side of the carriage 110. Therefore, when a printing process is performed, the transport unit 9 uses the carriage transport motor 91 to move the liquid ejection unit 3 and the carriage 110 back and forth in the Y-axis direction along the carriage guide shaft 96, and the medium transport motor 92 to transport the recording paper PP on the platen 95 in the X1 direction, thereby changing the relative position of the recording paper PP with respect to the liquid ejection unit 3 and enabling ink to land on the entire recording paper PP. In the first embodiment, the carriage transport motor 91 is an example of a "motor."

[0034] FIG. 3 is a schematic partial cross-sectional view of the liquid ejection head 32, in which the liquid ejection head 32 is cut so as to include the ejection portion D[m].

[0035] As shown in FIG. 3, the ejection section D[m] includes a piezoelectric element PZ[m], a cavity CV filled with ink, a nozzle N communicating with the cavity CV, and a vibration plate 321. The ejection section D[m] ejects ink from the cavity CV through the nozzle N when the piezoelectric element PZ[m] is driven by a supply drive signal Vin[m]. The cavity CV is a space defined by a cavity plate 324, a nozzle plate 323 in which the nozzle N is formed, and the vibration plate 321. The cavity CV communicates with a reservoir 325 via an ink supply port 326. The reservoir 325 communicates with the ink cartridge 120 corresponding to the ejection section D[m] via an ink intake port 327. The piezoelectric element PZ[m] includes an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric body Zm[m] disposed between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to a power supply line Ld set to a predetermined potential VBS. When a supply drive signal Vin[m] is supplied to the upper electrode Zu[m] and a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] is displaced in the Z1 and Z2 directions in response to the applied voltage, causing the piezoelectric element PZ[m] to vibrate. The lower electrode Zd[m] is bonded to the diaphragm 321. Therefore, when the piezoelectric element PZ[m] is driven to vibrate by the supply drive signal Vin[m], the diaphragm 321 also vibrates. The vibration of the diaphragm 321 changes the volume of the cavity CV and the pressure inside the cavity CV, causing the ink filled in the cavity CV to be ejected from the nozzle N.

[0036] FIG. 4 is a plan view showing an example of the arrangement of objects mounted on the carriage 110 when the carriage 110 is viewed in plan in the Z2 direction.

[0037] 4, the carriage 110 is mounted with an ultraviolet irradiation unit 5 and four liquid ejection units 3 aligned in the Y1 direction. Specifically, in the first embodiment, it is assumed that the ultraviolet irradiation unit 5 and four liquid ejection units 3 are mounted on the carriage 110 so that the four liquid ejection units 3 are positioned in the Y1 direction as viewed from the ultraviolet irradiation unit 5. Therefore, in the first embodiment, when the inkjet printer 1 executes a printing process, immediately after the liquid ejection units 3 move in the Y1 direction and eject ink onto the recording paper PP, the ultraviolet irradiation unit 5 moves in the Y1 direction and irradiates the ink ejected onto the recording paper PP with ultraviolet light to cure the ink.

[0038] 4, each liquid ejection unit 3 mounted on the carriage 110 is provided with a nozzle row NL. Here, the nozzle row NL is a plurality of nozzles N arranged to extend in a row in a predetermined direction. In the first embodiment, it is assumed, as an example, that each nozzle row NL is composed of M nozzles N arranged to extend in the X-axis direction.

[0039] As described above, the ultraviolet irradiation unit 5 includes an ultraviolet light source module 6 including a plurality of ultraviolet light sources E, and a temperature detection integrated circuit 7. In the first embodiment, as an example, it is assumed that the ultraviolet light source module 6 is provided between the temperature detection integrated circuit 7 and the liquid discharge unit 3 in the carriage 110. However, the present invention is not limited to this aspect. For example, the temperature detection integrated circuit 7 may be provided between the ultraviolet light source module 6 and the liquid discharge unit 3 in the carriage 110.

[0040] As described above, the ultraviolet light source module 6 includes multiple ultraviolet light sources E. In the first embodiment, it is assumed that NX×NY ultraviolet light sources E are arranged in the ultraviolet light source module 6 in a matrix of NX rows by NY columns, with NX rows in the X1 direction and NY columns in the Y1 direction. Here, the value NX is a natural number that satisfies "NX≧1". Also, the value NY is a natural number that satisfies "NY≧1". In the first embodiment, it is assumed, as an example, that the value NY is "4".

[0041] In the following description, the distance between two adjacent ultraviolet light sources E in the X1 direction is referred to as the distance dLX, and the distance between two adjacent ultraviolet light sources E in the Y1 direction is referred to as the distance dLY. In the first embodiment, for example, it is assumed that the distance dLX is equal to or less than the distance dLY. That is, in the first embodiment, for example, it is assumed that the arrangement distance in the X-axis direction of the plurality of ultraviolet light sources E arranged in a matrix is ​​equal to or less than the arrangement distance in the Y-axis direction. Note that the "distance between two adjacent ultraviolet light sources E" may be the distance between the centers of one of the two ultraviolet light sources E and the other ultraviolet light source E when the carriage 110 is viewed in a plan view in the Z2 direction, or may be the shortest distance between one of the two ultraviolet light sources E and the other ultraviolet light source E.

[0042] As illustrated in FIG. 4, in the first embodiment, it is assumed that the temperature detection integrated circuit 7 is disposed at an intermediate position in the X-axis direction among the ultraviolet irradiation units 5. More specifically, in the first embodiment, the temperature detection integrated circuit 7 is disposed at a position where the distance in the X-axis direction from the end in the X1 direction among the arrangement regions of the plurality of ultraviolet light sources E in the ultraviolet irradiation unit 5 is substantially the same as the distance in the X-axis direction from the end in the X2 direction among the arrangement regions of the plurality of ultraviolet light sources E in the ultraviolet irradiation unit 5. Here, "substantially the same" includes cases where, in addition to being completely identical, it can be regarded as identical considering errors, for example, cases where they are identical in design but different due to manufacturing errors, and cases where they are identical in specifications but different due to errors caused by disturbances or the like. In the first embodiment, "substantially the same" is a concept including cases where it can be regarded as identical considering an error of about 10%.

[0043] <<A.2. Outline of Ultraviolet Irradiation Unit 5>> Hereinafter, the configuration of the ultraviolet irradiation unit 5 will be described while referring to FIGS. 5 and 6.

[0044] FIG. 5 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5 when the ultraviolet irradiation unit 5 is cut by a plane having the X-axis direction as the normal direction.

[0045] As shown in FIG. 5, the ultraviolet irradiation unit 5 includes a substrate 51, a heat sink 52, and a housing 50, in addition to an ultraviolet light source module 6 including a plurality of ultraviolet light sources E and a temperature detection integrated circuit 7.

[0046] The substrate 51 is a flat plate-like member extending with the Z-axis direction as the normal direction, and has two surfaces with the Z-axis direction as the normal direction, a surface 51z1 facing the Z1 direction and a surface 51z2 facing the Z2 direction.

[0047] 5, a plurality of ultraviolet light sources E and a temperature detection integrated circuit 7 are provided on the surface 51z1. A housing 50 is also provided on the surface 51z1 so as to cover the plurality of ultraviolet light sources E and the temperature detection integrated circuit 7.

[0048] The housing 50 includes a frame 501 that covers the ultraviolet light sources E and the temperature detection integrated circuit 7, and a cover plate 502 that is provided in the Z1 direction when viewed from the ultraviolet light sources E.

[0049] The frame 501 is made of metal and prevents ink ejected from the liquid ejection unit 3 from adhering to electronic components such as the ultraviolet light source E and the temperature detection integrated circuit 7 provided on the substrate 51, and to various wirings provided on the substrate 51. However, the frame 501 may be made of a material other than metal, such as resin.

[0050] The cover plate 502 is made of glass that transmits ultraviolet light, and prevents ink ejected from the liquid ejection unit 3 from adhering to the ultraviolet light source E and various wirings provided on the substrate 51. However, the cover plate 502 may be made of a material other than glass, such as a transparent resin that transmits ultraviolet light.

[0051] In the first embodiment, the cover plate 502 is provided so as to be freely detachable from and attachable to the frame 501. Specifically, in the first embodiment, the cover plate 502 can be replaced from the ultraviolet irradiation unit 5 while the ultraviolet irradiation unit 5 remains installed in the inkjet printer 1, without removing the ultraviolet irradiation unit 5 from the inkjet printer 1. Therefore, according to the first embodiment, in cases such as when ink adheres to the cover plate 502 and the intensity of ultraviolet light irradiated onto the recording paper PP from the ultraviolet light source E decreases, the cover plate 502 can be easily replaced, and the maintainability of the ultraviolet irradiation unit 5 can be improved compared to an embodiment in which the cover plate 502 cannot be replaced.

[0052] As shown in FIG. 5 , a wall 61 is provided on the surface 51z1 between the ultraviolet light sources E and the liquid discharge unit 3, and a wall 62 is provided between the ultraviolet light sources E and the temperature detection integrated circuit 7. In the first embodiment, it is assumed that a wall surface 601 of the wall 61 facing the ultraviolet light source E and a wall surface 602 of the wall 62 facing the ultraviolet light source E are formed of a low-reflectivity material, such as black sponge, with an ultraviolet reflectance of approximately 0.1% to 10%. In the first embodiment, forming the wall surfaces 601 and 602 from sponge prevents ink mist from entering the inside of the cover plate 502 and reduces the possibility of the mist coming into contact with the ultraviolet light source E. More specifically, in the first embodiment, the wall surfaces 601 and 602 are formed of silicone sponge made of silicone. This increases the heat resistance of the wall surfaces 601 and 602 and also makes the wall surfaces 601 and 602 flame-retardant, which is suitable for an environment where ultraviolet rays are irradiated from the ultraviolet light source E. In the first embodiment, it is assumed that the wall surfaces 601 and 602 extend in the Z1 direction when the ultraviolet irradiation unit 5 is viewed in cross section in the X-axis direction.

[0053] 5, a heat sink 52 is provided on the surface 51z2. In the first embodiment, it is assumed that the heat sink 52 is made of aluminum.

[0054] In the first embodiment, the ultraviolet irradiation unit 5 is disposed so that the distance between it and the recording paper PP in the Z-axis direction is 1 mm or more and 15 mm or less. Therefore, according to the first embodiment, the distance between the ultraviolet irradiation unit 5 and the recording paper PP is secured to be 1 mm or more, thereby reducing the risk of contact between the ultraviolet irradiation unit 5 and the recording paper PP. Also, according to the first embodiment, the distance between the ultraviolet irradiation unit 5 and the recording paper PP is secured to be 15 mm or less, thereby ensuring the irradiation intensity of the ultraviolet light irradiated from the ultraviolet irradiation unit 5 onto the recording paper PP.

[0055] Furthermore, in the first embodiment, the ultraviolet light sources E provided in the ultraviolet irradiation unit 5 are arranged such that, for two ultraviolet light sources E adjacent to each other in the Y-axis direction, the irradiation area on the recording paper PP of the ultraviolet light emitted from one ultraviolet light source E overlaps with the irradiation area on the recording paper PP of the ultraviolet light emitted from the other ultraviolet light source E. Similarly, in the first embodiment, the ultraviolet light sources E provided in the ultraviolet irradiation unit 5 are arranged such that, for two ultraviolet light sources E adjacent to each other in the X-axis direction, the irradiation area on the recording paper PP of the ultraviolet light emitted from one ultraviolet light source E overlaps with the irradiation area on the recording paper PP of the ultraviolet light emitted from the other ultraviolet light source E.

[0056] Figure 6 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5 including the ultraviolet light source E and the substrate 51 when the ultraviolet irradiation unit 5 is cut along a plane whose normal direction is the X-axis direction so as to include the ultraviolet light source E.

[0057] 6, the ultraviolet light source E includes a light emitting unit 81, a lens unit 82, a package unit 83, and two connection wiring units 84. In the first embodiment, it is assumed that the ultraviolet light source E is a light emitting diode (UV-LED) that emits ultraviolet light.

[0058] The light-emitting section 81 is a light-emitting functional layer that emits ultraviolet light. One of the two connection wiring sections 84 functions as an anode that supplies holes to the light-emitting section 81. The other of the two connection wiring sections 84 functions as a cathode that supplies electrons to the light-emitting section 81. Holes supplied from one connection wiring section 84 and electrons supplied from the other connection wiring section 84 combine in the light-emitting section 81, causing the light-emitting section 81 to emit light and emit ultraviolet light.

[0059] The lens portion 82 seals the light-emitting portion 81 in the Z1 direction. In the first embodiment, it is assumed that the lens portion 82 is made of a transparent resin that transmits ultraviolet light. However, the lens portion 82 may also be made of silicone. In addition, it is preferable that the lens portion 82 is subjected to a water-repellent treatment.

[0060] The package unit 83 seals the light emitting unit 81 in the Y-axis direction and the X-axis direction. In the first embodiment, it is assumed that the package unit 83 is made of ceramic. However, the package unit 83 may also be made of resin.

[0061] As shown in FIG. 6, the substrate 51 includes a base material 511, an insulating layer 512, a resist 513, and a plurality of wirings 514.

[0062] The multiple wirings 514 are formed from a conductive material such as copper, and include one wiring 514 electrically connected to one connection wiring portion 84, and another wiring 514 electrically connected to the other connection wiring portion 84. In the first embodiment, it is assumed that gold plating 54 is disposed between the ultraviolet light source E and the substrate 51. In the first embodiment, it is assumed that one connection wiring portion 84 and one wiring 514 are electrically connected via the gold plating 54, and the other connection wiring portion 84 and the other wiring 514 are electrically connected via the gold plating 54.

[0063] The resist 513 electrically insulates one wiring 514 from another wiring 514 . The insulating layer 512 electrically insulates the wiring 514 from the substrate 511 .

[0064] The base material 511 is made of aluminum. In the first embodiment, it is assumed that the heat sink 52 is connected to the base material 511 by grease 53. However, the heat sink 52 may also be connected to the base material 511 by a heat dissipation sheet.

[0065] The heat generated in the light emitting unit 81 is dissipated, for example, through the connection wiring portion 84, the gold plating 54, the wiring 514, the insulating layer 512, the base material 511, the grease 53, and the heat sink 52. That is, at least a part of the heat generated by the ultraviolet light source E is dissipated through the base material 511. In addition, in the first embodiment, when the ultraviolet irradiation unit 5 is viewed in a plan view in the Z1 direction, the area of the base material 511 is larger than the area of the ultraviolet light source module 6 provided with the ultraviolet light source E on the substrate 51. Therefore, in the first embodiment, the heat generated by the ultraviolet light source E can be efficiently dissipated from the base material 511.

[0066] <<A.3. Control of the Ultraviolet Light Source E>> Hereinafter, the control of the ultraviolet light source E based on the temperature detected by the temperature detection integrated circuit 7 will be described with reference to FIGS. 7 and 8.

[0067] FIG. 7 is a functional block diagram showing an example of the configuration of the temperature detection integrated circuit 7.

[0068] As shown in FIG. 7, the temperature detection integrated circuit 7 includes a semiconductor temperature sensor 71 and a signal conversion circuit 72.

[0069] The semiconductor temperature sensor 71 detects the temperature and outputs an analog sensor output signal VT indicating the detection result. For example, the semiconductor temperature sensor 71 includes a constant current source and a diode, and outputs the potential difference between both ends of the diode that changes depending on the temperature as the sensor output signal VT.

[0070] The signal conversion circuit 72 converts the analog sensor output signal VT into a digital temperature detection signal DT. For example, the signal conversion circuit 72 includes an amplification circuit 721 that generates an amplified signal AT by amplifying the sensor output signal VT, and an AD conversion circuit 722 that generates the temperature detection signal DT by digitally converting the amplified signal AT.

[0071] In the temperature detection integrated circuit 7, the semiconductor temperature sensor 71 and the signal conversion circuit 72 are packaged as a single integrated circuit.

[0072] Fig. 8 is an explanatory diagram showing an example of temperature change in the radiant flux characteristics of the ultraviolet light source E. Specifically, in Fig. 8, the horizontal axis represents the temperature TE of the ultraviolet light source E, and the vertical axis represents the radiant flux RE of the ultraviolet light emitted from the ultraviolet light source E. Here, the radiant flux RE is the amount of energy of the ultraviolet light emitted from the ultraviolet light source E per unit time.

[0073] 8, in the first embodiment, the ultraviolet light source E emits ultraviolet rays with a radiant flux RE0 at a reference temperature TE0, emits ultraviolet rays with a radiant flux RE1 greater than the radiant flux RE0 at a temperature TE1 lower than the reference temperature TE0, and emits ultraviolet rays with a radiant flux RE2 less than the radiant flux RE0 at a temperature TE2 higher than the reference temperature TE0. In other words, in the first embodiment, the temperature TE of the ultraviolet light source E and the radiant flux RE of the ultraviolet rays emitted from the ultraviolet light source E have a negative correlation. In the first embodiment, the temperature TE1 is an example of a "first temperature," and the temperature TE2 is an example of a "second temperature."

[0074] In this way, the radiant flux RE of the ultraviolet light emitted from the ultraviolet light source E depends on the temperature of the ultraviolet light source E. In other words, the intensity of the ultraviolet light emitted from the ultraviolet light source E depends on the temperature inside the ultraviolet irradiation unit 5 in which the ultraviolet light source E is arranged. For this reason, for example, when the temperature inside the ultraviolet light source E becomes higher than the appropriate temperature, the intensity of the ultraviolet light emitted from the ultraviolet light source E becomes lower than the appropriate intensity. Therefore, for example, when the temperature inside the ultraviolet light source E becomes higher than the appropriate temperature, the ultraviolet irradiation unit 5 cannot irradiate the recording paper PP with ultraviolet light of the appropriate intensity, which can result in a deterioration in the quality of the image formed on the recording paper PP.

[0075] In contrast, according to the first embodiment, the control unit 2 generates the light source control signal SL based on the temperature detection signal DT output from the signal conversion circuit 72. For this reason, according to the first embodiment, it becomes possible to irradiate the recording paper PP from the ultraviolet irradiation unit 5 with ultraviolet light having an intensity corresponding to the temperature inside the ultraviolet irradiation unit 5, and it becomes possible to suppress a decrease in the image quality of the image formed on the recording paper PP.

[0076] <<A.4. Irradiation Intensity by Ultraviolet Irradiation Unit 5>> Hereinafter, a simulation (hereinafter referred to as "illuminance simulation") regarding the intensity (illuminance) of ultraviolet light irradiated from the ultraviolet irradiation unit 5 to the recording paper PP will be described while referring to FIGS. 9 and 10.

[0077] FIG. 9 is an explanatory diagram for explaining the premise of the illuminance simulation regarding the ultraviolet irradiation from the ultraviolet irradiation unit 5.

[0078] As shown in FIG. 9, hereinafter, the position in the Y-axis direction of the central axis AX indicating the central portion of the ultraviolet light source module 6 is set to "Y = 0", the position in the Y-axis direction of the end portion in the Y1 direction of the cover plate 502 is set to "Y = L", and the position in the Y-axis direction of the end portion in the Y2 direction of the cover plate 502 is set to "Y = -L". That is, hereinafter, it is assumed that the width of the cover plate 502 in the Y-axis direction is "2L". Here, the value L is a real number satisfying "L>0". And in the illuminance simulation, it is assumed that "L = 12.5 mm", that is, "2L = 25 mm". Also, hereinafter, the length in the Z-axis direction from the surface 51z1 of the substrate 51 on which the ultraviolet light source E is provided to the end portion in the Z1 direction of the cover plate 502 is referred to as the unit length HW. And in the illuminance simulation, it is assumed that the unit length HW is "8.1 mm". In the following description, the length in the Z-axis direction from the end of the cover plate 502 in the Z1 direction to the end of the platen 95 in the Z2 direction will be referred to as the platen gap HP. In the illuminance simulation, the platen gap HP is assumed to be 1.2 mm. In the illuminance simulation, it is assumed that the value NY is "4" and the value NX is "16." That is, in the illuminance simulation, it is assumed that a total of "64" ultraviolet light sources E are arranged in 16 rows and 4 columns in the ultraviolet light source module 6. In the illuminance simulation, it is assumed that the total amount of ultraviolet light emitted per second from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 is "83 W." In the illuminance simulation, it is assumed that the distance dLX is "4.4 mm" and the distance dLY is "4.6 mm." In the illuminance simulation, it is assumed that the reflectance of the wall surfaces 601 and 602 is "5%," the reflectance of the surface 51z1 is "10%," and the refractive index of the cover plate 502 is "1.5".

[0079] Fig. 10 is a diagram showing the results of an illuminance simulation according to the first embodiment. Specifically, Fig. 10 is a diagram showing the illuminance of ultraviolet light irradiated onto recording paper PP at a cut surface (hereinafter referred to as a "cut surface of interest") when recording paper PP placed on a platen 95 is cut along a plane normal to the X-axis direction under the conditions of the illuminance simulation shown in Fig. 9. Note that hereinafter, the illuminance simulation shown in Fig. 9 will be referred to as a first illuminance simulation.

[0080] As shown in FIG. 10, in the first illuminance simulation, the maximum illuminance on the recording paper PP was 5.2 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.18L" to "1.18L." In addition, in the first illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5 per second is "62W."

[0081] <<A.5. Prior Art Example>> Hereinafter, while referring to FIGS. 11 and 12, the ultraviolet irradiation unit 5 according to the first embodiment and the ultraviolet irradiation unit according to the prior art example will be described.

[0082] FIG. 11 is a diagram showing an overview of the ultraviolet irradiation unit 5 according to the first embodiment, an overview of the ultraviolet irradiation unit according to the prior art example 1, and an overview of the ultraviolet irradiation unit according to the prior art example 2. Note that the ultraviolet irradiation unit according to the prior art example 1 is an ultraviolet irradiation unit manufactured and sold by another company (Company A), and the ultraviolet irradiation unit according to the prior art example 2 is an ultraviolet irradiation unit manufactured and sold by another company (Company B).

[0083] As shown in FIG. 11, the ultraviolet irradiation unit 5 according to the first embodiment is provided with one unit having a power consumption of 160 W, and the total power consumption is 160 W. On the other hand, the ultraviolet irradiation unit according to the prior art example 1 is provided with two units having a power consumption of 30 W, and the total power consumption is 60 W. Also, the ultraviolet irradiation unit according to the prior art example 2 is provided with one unit having a power consumption of 250 W, and the total power consumption is 250 W. Thus, like the ultraviolet irradiation unit according to the prior art example, the ultraviolet irradiation unit 5 according to the first embodiment has a large power consumption, and it is important to efficiently dissipate the heat generated in the ultraviolet irradiation unit 5.

[0084] As shown in FIG. 11, in the ultraviolet irradiation unit 5 according to the first embodiment, the base material in the substrate 51 included in the ultraviolet irradiation unit 5 is formed of aluminum. That is, the substrate 51 provided in the ultraviolet irradiation unit 5 is a so-called aluminum substrate. On the other hand, the base material of the substrate included in the ultraviolet irradiation unit according to the prior art example 1 is formed of copper, and similarly, the base material of the substrate included in the ultraviolet irradiation unit according to the prior art example 2 is also formed of copper. That is, the substrates provided in the ultraviolet irradiation units according to the prior art example 1 and the prior art example 2 are so-called copper substrates.

[0085] FIG. 12 is a diagram showing the thermal conductivity and specific gravity of various metals.

[0086] As shown in Figure 12, the thermal conductivity of copper is 398 W / mk. Therefore, copper has a higher thermal conductivity than aluminum (236 W / mk), iron (67 W / mk), and stainless steel (16 W / mk). In other words, by using a copper substrate as the substrate of an ultraviolet irradiation unit, as in the conventional example, it is possible to efficiently dissipate heat generated in the ultraviolet irradiation unit. Although materials with higher thermal conductivity than copper exist, such as silver (398 W / mk) and diamond (1000 W / mk), their high cost makes them unrealistic for use as substrates for ultraviolet irradiation units. For this reason, copper substrates have traditionally been used as substrates for ultraviolet irradiation units.

[0087] On the other hand, as shown in Figure 12, the specific gravity of aluminum is 2.7 g / cm 3 Therefore, the specific gravity of copper is 8.9 g / cm 3 , specific gravity of iron 7.8g / cm 3 , and the specific gravity of stainless steel is 7.9 g / cm 3 The specific gravity of aluminum is smaller than that of aluminum. Therefore, the ultraviolet irradiation unit 5 according to the first embodiment can reduce the weight of the substrate 51 and the ultraviolet irradiation unit 5 as a whole, compared to conventional ultraviolet irradiation units such as the ultraviolet irradiation unit according to Conventional Example 1 and the ultraviolet irradiation unit according to Conventional Example 2. As a result, the ultraviolet irradiation unit 5 according to the first embodiment can reduce the load on the carriage transport motor 91 that drives the carriage 110 when the ultraviolet irradiation unit 5 is mounted on the carriage 110 and moved. In other words, the ultraviolet irradiation unit 5 according to the first embodiment can extend the life of the carriage transport motor 91 and reduce the amount of power required to drive the carriage transport motor 91, compared to the ultraviolet irradiation unit according to Conventional Example 1 or the ultraviolet irradiation unit according to Conventional Example 2 mounted on the carriage 110.

[0088] As described above, the thermal conductivity of aluminum is lower than that of copper, but higher than that of iron and stainless steel. Therefore, the ultraviolet irradiation unit 5 according to the first embodiment can reduce the load on the carriage transport motor 91 that drives the carriage 110 and efficiently dissipate heat in the ultraviolet irradiation unit 5.

[0089] In addition, ultraviolet irradiation units that generate a large amount of heat are typically equipped with heat sinks to improve the heat dissipation of the ultraviolet irradiation units. Heat sinks are typically made of aluminum. Therefore, when an aluminum heat sink is attached to an ultraviolet irradiation unit that uses a copper substrate, such as the ultraviolet irradiation units of Conventional Example 1 and Conventional Example 2, corrosion is likely to occur at the interface between the copper substrate and the aluminum. Therefore, when an aluminum heat sink is attached to an ultraviolet irradiation unit that uses a copper substrate, such as the conventional examples, a heat dissipation sheet is typically interposed between the copper substrate and the heat sink to prevent corrosion at the interface between the copper substrate and the aluminum heat sink. Therefore, ultraviolet irradiation units that use a copper substrate, such as the conventional examples, can have problems such as an increase in the size of the ultraviolet irradiation unit, an increase in the cost of the ultraviolet irradiation unit, and an increase in the number of parts in the ultraviolet irradiation unit.

[0090] In contrast, the ultraviolet irradiation unit 5 according to the first embodiment employs an aluminum substrate as the substrate 51, in which the base material 511 is made of aluminum. Therefore, in the ultraviolet irradiation unit 5 according to the first embodiment, corrosion at the interface between the base material 511 made of aluminum and the heat sink 52 made of aluminum is not an issue. Therefore, in the ultraviolet irradiation unit 5 according to the first embodiment, it is not necessary to interpose a heat dissipation sheet between the substrate 51 and the heat sink 52; it is sufficient to interpose grease 53 between the substrate 51 and the heat sink 52. This allows the ultraviolet irradiation unit 5 according to the first embodiment to be smaller, less expensive, and with fewer components, compared to conventional ultraviolet irradiation units employing a copper substrate. As a base metal, aluminum is second only to iron in production volume, and is said to exceed even iron in terms of the ratio of reserves to current demand. Aluminum is also considered to be a metal with superior recyclability compared to copper. Meanwhile, copper resources are limited, and it is predicted that by 2050, copper usage will exceed current reserves. In response to this, the first embodiment employs an aluminum substrate having a base material 511 formed from aluminum in the ultraviolet irradiation unit 5. Therefore, the first embodiment can reduce the environmental impact compared to an embodiment employing a copper substrate for the ultraviolet irradiation unit 5, and can be said to be an embodiment that takes into account future "copper shortages."

[0091] As shown in FIG. 11, the temperature sensor included in the ultraviolet irradiation unit according to Conventional Example 1 is a thermistor. Similarly, the temperature sensor included in the ultraviolet irradiation unit according to Conventional Example 2 is also a thermistor. Thus, in ultraviolet irradiation units, it has been common to employ a thermistor as the temperature sensor for detecting the temperature of the ultraviolet irradiation unit. However, a thermistor outputs the detected temperature as an analog signal. Therefore, when the ultraviolet irradiation unit is mounted on a carriage together with the liquid ejection unit, noise caused by various signals for driving the liquid ejection unit is superimposed on the analog signal output from the thermistor, making it difficult to accurately grasp the temperature of the ultraviolet irradiation unit.

[0092] In contrast, in the ultraviolet irradiation unit 5 according to the first embodiment, an integrated circuit (that is, the temperature detection integrated circuit 7) is provided as the temperature sensor for detecting the temperature of the ultraviolet irradiation unit 5. And in the ultraviolet irradiation unit 5 according to the first embodiment, the temperature detection integrated circuit 7 outputs a temperature detection signal DT, which is a digital signal indicating the detection result of the temperature of the ultraviolet irradiation unit 5. For this reason, according to the first embodiment, even when the ultraviolet irradiation unit 5 is mounted on the carriage 110 together with the liquid ejection unit 3, it is possible to suppress the temperature detection signal DT output from the temperature detection integrated circuit 7 from being affected by various signals such as the drive signal Com for driving the liquid ejection unit 3. That is, according to the first embodiment, it becomes possible to accurately grasp the temperature of the ultraviolet irradiation unit 5 as compared with the mode of employing a thermistor as the temperature sensor as in the prior art.

[0093] <<B. Second Embodiment>> Hereinafter, the inkjet printer according to the second embodiment will be described while referring to FIGS. 13 to 22. In addition, for elements whose operations and functions are the same as those in the first embodiment in each of the embodiments illustrated below, the reference numerals used in the description of the first embodiment are reused, and the detailed description of each is appropriately omitted.

[0094] 13 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5B provided in the inkjet printer according to the second embodiment, taken along a plane normal to the X-axis direction. The inkjet printer according to the second embodiment has the same configuration as the inkjet printer 1 according to the first embodiment, except that it includes an ultraviolet irradiation unit 5B instead of the ultraviolet irradiation unit 5.

[0095] As shown in FIG. 13, the ultraviolet irradiation unit 5B has the same configuration as the ultraviolet irradiation unit 5 of the first embodiment, except that it has a wall portion 61B instead of the wall portion 61 and a wall portion 62B instead of the wall portion 62.

[0096] The wall portion 61B has a wall surface 601B facing the ultraviolet light source E. When the ultraviolet irradiation unit 5B is viewed in cross section in the X-axis direction, the wall surface 601B extends in a direction between the Z1 direction and the Y1 direction, and forms an angle θ1 with the Z1 direction. Here, the angle θ1 is an angle between 0 degrees and 30 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 5 degrees and 10 degrees. The wall surface 601B is a reflective surface with a reflectance of 70% or more, preferably a reflective surface with a reflectance of 85% or more, and more preferably a reflective surface with a reflectance of 90% or more.

[0097] The wall portion 62B has a wall surface 602B facing the ultraviolet light source E. When the ultraviolet irradiation unit 5B is viewed in cross section in the X-axis direction, the wall surface 602B extends in a direction between the Z1 direction and the Y2 direction, and forms an angle θ2 with the Z1 direction. Here, the angle θ2 is an angle between 0 degrees and 30 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 5 degrees and 10 degrees. The wall surface 602B is a reflective surface with a reflectance of 70% or more, preferably a reflective surface with a reflectance of 85% or more, and more preferably a reflective surface with a reflectance of 90% or more.

[0098] FIG. 14 is an explanatory diagram for explaining the premise of the illuminance simulation related to ultraviolet radiation from the ultraviolet radiation unit 5B.

[0099] As shown in FIG. 14 , in the illuminance simulation of the second embodiment, as in the first embodiment, the position of the end of the cover plate 502 in the Y1 direction in the Y-axis direction is assumed to be “Y=L,” the position of the end of the cover plate 502 in the Y2 direction in the Y-axis direction is assumed to be “Y=−L,” and the width of the cover plate 502 in the Y-axis direction is assumed to be “2L=25 mm.” Also, in the illuminance simulation of the second embodiment, as in the first embodiment, the unit length HW is assumed to be “8.1 mm,” the platen gap HP is assumed to be “1.2 mm,” and the illuminance simulation of the second embodiment, as in the first embodiment, the illuminance simulation of the second embodiment, as in the first embodiment, the number of NY columns is assumed to be “4,” the number of NX rows is assumed to be “16,” the spacing dLX is assumed to be “4.4 mm,” and the spacing dLY is assumed to be “4.6 mm.” Also, in the illuminance simulation of the second embodiment, as in the first embodiment, the total amount of ultraviolet light emitted per second from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 is assumed to be “83 W.” In the illumination simulation in the second embodiment, similarly to the first embodiment, it is assumed that the reflectance of the surface 51z1 is "10%" and the refractive index of the cover plate 502 is "1.5." In the illumination simulation in the second embodiment, it is assumed that the reflectance of the wall surface 601B and the wall surface 602B is "90%."

[0100] As described above, when the ultraviolet irradiation unit 5B is viewed in cross section in the X-axis direction, the wall surface 601B extends in a direction between the Z1 direction and the Y1 direction, at an angle θ1 with respect to the Z1 direction. Therefore, as shown in FIG. 14, when the distance from the substrate 51 in the Z1 direction is dZ1 (an example of a "first distance"), the distance dY1 in the Y1 direction between the wall surface 601B and the liquid discharge unit 3 is equal to or greater than the distance dY2 in the Y1 direction between the wall surface 601B and the liquid discharge unit 3 when the distance from the substrate 51 in the Z1 direction is dZ2 (an example of a "second distance") that is longer than the distance dZ1. However, when the angle θ1 is "θ1>0," the distance dY1 is longer than the distance dY2.

[0101] Figure 15 shows the results of an illuminance simulation (hereinafter referred to as the "second illuminance simulation") of the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5B at the target cross section when angle θ1 is set to "0 degrees" and angle θ2 is set to "0 degrees" in Figure 14.

[0102] As shown in FIG. 15, in the second illuminance simulation, the maximum illuminance on the recording paper PP was 6.3 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.34L" to "1.34L." In addition, in the second illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "75W."

[0103] Figure 16 shows the results of an illuminance simulation (hereinafter referred to as the "third illuminance simulation") regarding the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5B at the target cross section when angle θ1 is set to "5 degrees" and angle θ2 is set to "5 degrees" in Figure 14.

[0104] As shown in FIG. 16, in the third illuminance simulation, the maximum illuminance on the recording paper PP was 6.0 W / cm 2", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.08L" to "1.08L." In addition, in the third illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "76W."

[0105] Figure 17 shows the results of an illuminance simulation (hereinafter referred to as the "fourth illuminance simulation") regarding the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5B at the target cross section when angle θ1 is set to "10 degrees" and angle θ2 is set to "10 degrees" in Figure 14.

[0106] As shown in FIG. 17, in the fourth illuminance simulation, the maximum illuminance on the recording paper PP was 5.7 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.34L" to "1.34L." Furthermore, in the fourth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "77W."

[0107] Figure 18 shows the results of an illuminance simulation (hereinafter referred to as the "fifth illuminance simulation") regarding the illuminance of ultraviolet light irradiated from the ultraviolet irradiation unit 5B onto the recording paper PP at the target cross section when the angle θ1 in Figure 14 is set to "15 degrees" and the angle θ2 is set to "15 degrees".

[0108] As shown in FIG. 18, in the fifth illuminance simulation, the maximum illuminance on the recording paper PP was 5.4 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.36L" to "1.36L." In addition, in the fifth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "77W."

[0109] Figure 19 shows the results of an illuminance simulation (hereinafter referred to as the "sixth illuminance simulation") regarding the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5B at the target cross section when angle θ1 is set to "20 degrees" and angle θ2 is set to "20 degrees" in Figure 14.

[0110] As shown in FIG. 19, in the sixth illuminance simulation, the maximum illuminance on the recording paper PP was 5.2 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.38L" to "1.38L." In addition, in the sixth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "77W."

[0111] Figure 20 shows the results of an illuminance simulation (hereinafter referred to as the "seventh illuminance simulation") regarding the illuminance of ultraviolet light irradiated from the ultraviolet irradiation unit 5B onto the recording paper PP at the target cross section when the angle θ1 in Figure 14 is set to "30 degrees" and the angle θ2 is set to "30 degrees".

[0112] As shown in FIG. 20, in the seventh illuminance simulation, the maximum illuminance on the recording paper PP was 5.2 W / cm 2 ", and the reach range of ultraviolet rays on the target cross section is in the range from "-1.24L" to "1.24L." Furthermore, in the seventh illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B per second is "76W."

[0113] Figure 21 shows the results of an illuminance simulation (hereinafter referred to as the "eighth illuminance simulation") regarding the illuminance of ultraviolet light irradiated from the ultraviolet irradiation unit 5B onto the recording paper PP at the target cross section when the angle θ1 in Figure 14 is set to "45 degrees" and the angle θ2 is set to "45 degrees".

[0114] As shown in FIG. 21, in the eighth illuminance simulation, the maximum illuminance on the recording paper PP was 5.1 W / cm 2」, and the range of the ultraviolet ray reaching the target cut surface is from "-1.45L" to "1.45L". In the eighth illuminance simulation, the total value of the illuminance of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B in one second is "76W".

[0115] FIG. 22 is a diagram showing the results from the second illuminance simulation to the eighth illuminance simulation shown in FIGS. 15 to 21. In FIG. 22, the solid line FW indicates the maximum illuminance WM in each illuminance simulation, and the broken line FK indicates the irradiation efficiency α in each illuminance simulation. Here, the irradiation efficiency α is a value obtained by dividing the total value of the illuminance irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in one second in each illuminance simulation by the total amount of the ultraviolet rays emitted from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 in one second. Also, in FIG. 22, "θ1 = θ2 = θ".

[0116] As shown by the solid line FW in FIG. 22, as the angle θ decreases, the maximum illuminance WM increases. Therefore, in order to more surely cure the ink by ultraviolet irradiation, it is preferable to increase the maximum illuminance WM by decreasing the angle θ. Thus, from the viewpoint of the certainty of ink curing, for example, the range where the angle θ is "0 degrees or more and 15 degrees or less" is preferable, and the range where the angle θ is "0 degrees or more and 10 degrees or less" is more preferable. On the other hand, in order to increase the irradiation efficiency α of the ultraviolet rays from the ultraviolet irradiation unit 5B, the range where the angle θ is "5 degrees or more and 45 degrees or less" is preferable.

[0117] In contrast, in the second embodiment, the angle θ is set to "0 degrees or more and 30 degrees or less", preferably, the angle θ is set to "5 degrees or more and 15 degrees or less", and more preferably, the angle θ is set to "5 degrees or more and 10 degrees or less". Therefore, according to the second embodiment, it is possible to achieve both the improvement of the certainty of ink curing by increasing the maximum illuminance WM and the reduction of the power related to the drive of the ultraviolet irradiation unit 5B by increasing the irradiation efficiency α.

[0118] <<C. Third Embodiment>> An inkjet printer according to the third embodiment will be described below with reference to Figures 23 to 26. Note that for elements in the following exemplary embodiments whose actions and functions are similar to those of the first or second embodiment, the reference numerals used in the description of the first or second embodiment will be used, and detailed description of each will be omitted where appropriate.

[0119] 23 is a cross-sectional view showing an example of the configuration of an ultraviolet irradiation unit 5C provided in an inkjet printer according to the third embodiment, taken along a plane normal to the X-axis direction. The inkjet printer according to the third embodiment has the same configuration as the inkjet printer 1 according to the first embodiment, except that it includes an ultraviolet irradiation unit 5C instead of the ultraviolet irradiation unit 5.

[0120] 23, the ultraviolet irradiation unit 5C has a similar configuration to the ultraviolet irradiation unit 5 according to the first embodiment, except that it includes a wall 61B instead of the wall 61. That is, the ultraviolet irradiation unit 5C includes a wall 61B having a wall surface 601B with a reflectance of 70% or more between the ultraviolet light source E and the liquid discharging unit 3, and a wall 62 having a wall surface 602 with a reflectance of approximately 0.1% to 10% on the opposite side of the ultraviolet light source E from the liquid discharging unit 3. In other words, in the ultraviolet irradiation unit 5C, the light absorptance of the wall surface 602 of the wall 62 provided on the opposite side of the ultraviolet light source E from the liquid discharging unit 3 is higher than the light absorptance of the wall surface 601B of the wall 61B provided between the ultraviolet light source E and the liquid discharging unit 3. Furthermore, in the third embodiment, similarly to the first or second embodiment, when the ultraviolet irradiation unit 5C is viewed in cross section in the X-axis direction, it is assumed that the wall surface 601B extends in a direction between the Z1 direction and the Y1 direction and forms an angle θ1 with the Z1 direction, and the wall surface 602 extends in the Z1 direction.

[0121] FIG. 24 is an explanatory diagram for explaining the premise of the illuminance simulation related to ultraviolet radiation from the ultraviolet radiation unit 5C.

[0122] As shown in FIG. 24 , in the illuminance simulation of the third embodiment, as in the first embodiment, the position of the Y1-direction end of the cover plate 502 in the Y-axis direction is assumed to be “Y=L,” the position of the Y2-direction end of the cover plate 502 in the Y-axis direction is assumed to be “Y=−L,” and the width of the cover plate 502 in the Y-axis direction is assumed to be “2L=25 mm.” Also, in the illuminance simulation of the third embodiment, as in the first embodiment, the unit length HW is assumed to be “8.1 mm,” the platen gap HP is assumed to be “1.2 mm,” and the illuminance simulation of the third embodiment is assumed to be “4” for the NY columns, “16” for the NX rows, the spacing dLX is assumed to be “4.4 mm,” and the spacing dLY is assumed to be “4.6 mm.” Also, in the illuminance simulation of the third embodiment, as in the first embodiment, the total amount of ultraviolet light emitted per second from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 is assumed to be “83 W.” In addition, in the illumination simulation for the third embodiment, as in the first and second embodiments, it is assumed that the reflectance of surface 51z1 is "10%", the reflectance of wall surface 601B is "90%," the reflectance of wall surface 602 is "5%," and the refractive index of cover plate 502 is "1.5".

[0123] Figure 25 shows the results of an illuminance simulation (hereinafter referred to as the "ninth illuminance simulation") regarding the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5C at the target cross section when angle θ1 is set to "0 degrees" in Figure 24.

[0124] As shown in FIG. 25, in the ninth illuminance simulation, the maximum illuminance on the recording paper PP was 5.9 W / cm 2", and the reach of ultraviolet rays on the target cross section is in the range from "-1.34L" to "1.29L." Furthermore, in the ninth illuminance simulation, the total illuminance of ultraviolet rays irradiated per second from the ultraviolet irradiation unit 5C is "68W." Furthermore, in the ninth illuminance simulation, the illuminance in the region where "Y>0" is lower than the illuminance in the region where "Y<0" is lower. In other words, in the ninth illuminance simulation, the illuminance in the region closer to the liquid discharge unit 3 than the central axis AX is lower than the illuminance in the region farther from the liquid discharge unit 3 than the central axis AX.

[0125] Figure 26 shows the results of an illuminance simulation (hereinafter referred to as the "10th illuminance simulation") regarding the illuminance of ultraviolet light irradiated onto recording paper PP from ultraviolet irradiation unit 5C at the target cross section when angle θ1 is set to "30 degrees" in Figure 24.

[0126] As shown in FIG. 26, in the tenth illuminance simulation, the maximum illuminance on the recording paper PP was 5.4 W / cm 2 ", and the reach of ultraviolet light on the target cross section is in the range from "-1.34L" to "1.33L." Furthermore, in the tenth illuminance simulation, the total illuminance of ultraviolet light emitted from the ultraviolet irradiation unit 5C per second is "70W." Furthermore, in the tenth illuminance simulation, the illuminance in the region where "Y>0" is lower than the illuminance in the region where "Y<0" is lower. In other words, in the tenth illuminance simulation, the illuminance in the region closer to the liquid discharge unit 3 than the central axis AX is lower than the illuminance in the region farther from the liquid discharge unit 3 than the central axis AX.

[0127] As described above, according to the third embodiment, since the reflectance of the wall surface 602 is lower than the reflectance of the wall surface 601B, the illuminance of the ultraviolet rays irradiated in the Y1 direction from the ultraviolet irradiation unit 5C can be made lower than the illuminance of the ultraviolet rays irradiated in the Y2 direction from the ultraviolet irradiation unit 5C. Therefore, according to the third embodiment, compared with the second embodiment described above, the amount of ultraviolet rays that are reflected by the recording paper PP and reach the liquid ejection unit 3 among the ultraviolet rays irradiated from the ultraviolet irradiation unit 5C can be reduced. That is, according to the third embodiment, compared with the second embodiment described above, it is possible to reduce the possibility of occurrence of ejection abnormalities in the ejection unit D due to irradiation of ultraviolet rays on the liquid ejection unit 3.

[0128] <<D. Modified Example>> Each of the above embodiments can be variously modified. Specific modification modes are exemplified below. Two or more modes arbitrarily selected from the following examples can be appropriately combined within a range that does not conflict with each other. In the modified examples exemplified below, for elements whose actions and functions are equivalent to those of the embodiments, the reference numerals referred to in the above description are used, and the detailed description of each is appropriately omitted.

[0129] <<D.1. Modified Example 1>> In the first to third embodiments described above, the lens unit 82 included in the ultraviolet light source E may be characterized in that the height dEZ of the lens unit 82 in the Z-axis direction is longer than the width dEY of the lens unit 82 in the Y-axis direction and longer than the width dEX (not shown) of the lens unit 82 in the X-axis direction.

[0130] FIG. 27 is a cross-sectional view showing an example of the configuration of the ultraviolet light source E when the ultraviolet light source E according to the modified example 1 is cut by a plane having the X-axis direction as the normal direction.

[0131] As shown in FIG. 27, the ultraviolet light source E according to the modified example 1 includes a light emitting unit 81, a lens unit 82, a package unit 83, and a connection wiring unit 84, similar to the ultraviolet light source E according to the embodiment. In the modified example 1, the lens unit 82 includes a cylindrical base portion 821 and a hemispherical tip portion 822.

[0132] The base portion 821 has a height dEZ1 in the Z-axis direction and a width dEY in the X-axis and Y-axis directions. That is, the base portion 821 has a circular shape with a diameter dEY when viewed from the Z-axis direction.

[0133] The tip portion 822 is connected to the base portion 821 in the Z1 direction when viewed from the base portion 821, and has a height dEZ2 in the Z-axis direction and a width dEY in the X-axis and Y-axis directions. In other words, the tip portion 822 has a circular shape with a diameter dEY when viewed from the Z-axis direction.

[0134] In this modified example, the lens portion 82 has a shape such that the heights dEZ1 and dEZ2 and the width dEY satisfy the relationship "dEZ1+dEZ2=dEZ>dEY." In other words, in this modified example, the lens portion 82 has a shape such that the length of the lens portion 82 in the Z-axis direction is longer than the diameter of the base portion 821.

[0135] 28 is a diagram showing an example of the directional characteristics of the ultraviolet light source E in this modification and the directional characteristics of an ultraviolet light source in a comparative example. The ultraviolet light source in the comparative example has the same configuration as the ultraviolet light source E in the first modification, except that the length of the lens portion 82 in the Z-axis direction is shorter than the diameter of the base portion 821.

[0136] 28, the ultraviolet light source E according to Modification 1 has high directivity, as represented by curve FS1. On the other hand, the ultraviolet light source in the comparative example has low directivity, as represented by curve FS2. Therefore, by employing the ultraviolet light source E according to Modification 1 as the ultraviolet light source E used in the ultraviolet irradiation unit 5 (or the ultraviolet irradiation unit 5B or the ultraviolet irradiation unit 5C), it is possible to improve the irradiation efficiency of ultraviolet light from the ultraviolet irradiation unit 5 and reduce the possibility that the ultraviolet light emitted from the ultraviolet irradiation unit 5 will be reflected by the recording paper PP and reach the liquid ejection unit 3.

[0137] <<D.2. Modified Example 2>> In the above-described first to third embodiments and Modified Example 1, in the inkjet printer 1, the mode in which one ultraviolet irradiation unit 5 is provided in the Y2 direction as viewed from the liquid discharge unit 3 has been exemplified and described. However, the present invention is not limited to such a mode. The inkjet printer 1 may be provided with a total of two ultraviolet irradiation units 5, namely, one ultraviolet irradiation unit 5 in the Y2 direction as viewed from the liquid discharge unit 3 and one ultraviolet irradiation unit 5 in the Y1 direction as viewed from the liquid discharge unit 3. In this case, the inkjet printer 1 discharges ink from the liquid discharge unit 3 onto the recording paper PP while moving the carriage 110 in the Y1 direction, and irradiates the recording paper PP with ultraviolet rays from the ultraviolet irradiation unit 5 provided in the Y2 direction as viewed from the liquid discharge unit 3. Then, while moving the carriage 110 in the Y2 direction, the inkjet printer 1 discharges ink from the liquid discharge unit 3 onto the recording paper PP and irradiates the recording paper PP with ultraviolet rays from the ultraviolet irradiation unit 5 provided in the Y1 direction as viewed from the liquid discharge unit 3, thereby executing the printing process.

[0138] <<D.3. Modified Example 3>> In the above-described first to third embodiments, Modified Example 1, and Modified Example 2, the case where the inkjet printer 1 includes four liquid discharge units 3 has been assumed. However, the present invention is not limited to such a mode. The inkjet printer 1 may include one or more and three or fewer liquid discharge units 3, or may include five or more liquid discharge units 3.

[0139] <<E. Supplementary Note>> Aspects understood from the above description are described below. For the sake of easy understanding of each aspect, hereinafter, the reference numerals in the drawings are appended in parentheses for convenience, but this is not intended to limit the present invention to the illustrated aspects.

[0140] <<E.1. Supplementary Note 1>> Hereinafter, the inkjet printer 1 according to Supplementary Note 1 will be described.

[0141] <<Appendix 1-1>> The inkjet printer 1 according to Appendix 1-1 comprises a liquid ejection unit 3 that ejects ink that hardens when exposed to ultraviolet light onto recording paper PP, an ultraviolet irradiation unit 5 that irradiates the ink ejected onto the recording paper PP with ultraviolet light, a carriage 110 that carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5 and moves over the recording paper PP, and a carriage transport motor 91 for moving the carriage 110, and is characterized in that the ultraviolet irradiation unit 5 comprises a substrate 51 and an ultraviolet light source E that is disposed on the substrate 51 and emits ultraviolet light, and the substrate 51 has an aluminum base material 511.

[0142] According to Supplementary Note 1-1, the ultraviolet irradiation unit 5 employs a substrate 51 having an aluminum base material 511, which enables the ultraviolet irradiation unit 5 to be lighter than in an embodiment in which the ultraviolet irradiation unit employs a substrate having a copper base material. Therefore, according to Supplementary Note 1-1, the load on the carriage transport motor 91 that moves the carriage 110 on which the ultraviolet irradiation unit 5 is mounted is reduced, thereby enabling the life of the carriage transport motor 91 to be extended and the amount of power required to drive the carriage transport motor 91 to be reduced.

[0143] <<Appendix 1-2>> The inkjet printer 1 according to Supplementary Note 1-2 is the inkjet printer 1 according to Supplementary Note 1-1, characterized in that at least a portion of the heat generated in the ultraviolet light source E is dissipated via the base material 511.

[0144] <<Appendix 1-3>> The inkjet printer 1 according to Supplementary Note 1-3 is the inkjet printer 1 according to Supplementary Note 1-1 or Supplementary Note 1-2, characterized in that the surface area of ​​the substrate 51 is larger than the area of ​​the region of the substrate 51 where the ultraviolet light source E is provided.

[0145] According to Supplementary Note 1-3, compared to an embodiment in which the surface area of ​​the substrate 51 is smaller than the area of ​​the region in which the ultraviolet light source E is provided, it is possible to dissipate the heat generated in the ultraviolet light source E more efficiently.

[0146] <<Appendix 1-4>> The inkjet printer 1 according to Supplementary Note 1-4 is the inkjet printer 1 according to Supplementary Note 1-1 to Supplementary Note 1-3, characterized in that an aluminum heat sink 52 is attached to the base material 511.

[0147] According to Supplementary Note 1-4, since the aluminum heat sink 52 is attached to the aluminum base material 511, it is possible to reduce the possibility of corrosion occurring at the interface between the base material 511 and the heat sink 52, compared to an embodiment in which the aluminum heat sink 52 is attached to a copper base material. Therefore, according to Supplementary Note 1-4, it is not necessary to interpose a heat dissipation sheet between the base material 511 and the heat sink 52, and it is possible to reduce the size of the ultraviolet irradiation unit 5, reduce the number of parts of the ultraviolet irradiation unit 5, and improve the design freedom of the ultraviolet irradiation unit 5.

[0148] <<Appendix 1-5>> The inkjet printer 1 according to Supplementary Note 1-5 is the inkjet printer 1 according to Supplementary Note 1-1 to Supplementary Note 1-4, characterized in that the ultraviolet light source E is a light-emitting diode (UV-LED) that emits ultraviolet light.

[0149] According to Appendix 1-5, since a light-emitting diode is used as the ultraviolet light source E, it generates less heat, is smaller, and is suitable for mounting on the carriage 110 compared to embodiments that use conventional light sources such as high-pressure mercury lamps or xenon lamps as the ultraviolet light source E.

[0150] <<Appendix 1-6>> The inkjet printer 1 according to Supplementary Note 1-6 is the inkjet printer 1 according to Supplementary Notes 1-1 to 1-5, and is characterized in that a semiconductor temperature sensor 71 is provided on the substrate 51.

[0151] According to Supplementary Note 1-6, it becomes possible to grasp the temperature of the ultraviolet irradiation unit 5, and based on the temperature of the ultraviolet irradiation unit 5, it becomes possible to judge whether to stop the ultraviolet light source E or adjust the light emission intensity of the ultraviolet light source E, etc.

[0152] <<Supplementary Note 1-7>> The inkjet printer 1 according to Supplementary Note 1-7 is the inkjet printer 1 according to Supplementary Notes 1-1 to 1-6, and is characterized in that a signal conversion circuit 72 for converting the output from the semiconductor temperature sensor 71 into a digital signal is provided on the substrate 51, and the semiconductor temperature sensor 71 and the signal conversion circuit 72 are packaged as a temperature detection integrated circuit 7 which is an integrated circuit.

[0153] According to Supplementary Note 1-7, it becomes possible to reduce the possibility that noise is superimposed on the output signal from the temperature detection integrated circuit 7 as compared with the aspect where the output from the temperature detection integrated circuit 7 is an analog signal.

[0154] <<Supplementary Note 1-8>> The inkjet printer 1 according to Supplementary Note 1-8 is the inkjet printer 1 according to Supplementary Notes 1-1 to 1-7, and is characterized in that the ultraviolet irradiation unit 5 includes a housing 50 including a cover plate 502 that transmits ultraviolet rays and a frame 501, and the substrate 51 and the ultraviolet light source E are provided inside the housing 50.

[0155] <<E.2. Supplementary Note 2>> ​​​​​​The inkjet printer 1 according to Appendix 2-1 comprises a liquid ejection unit 3 that ejects ink that hardens when exposed to ultraviolet light onto recording paper PP; an ultraviolet irradiation unit 5 that irradiates ultraviolet light onto the ink ejected onto the recording paper PP; a carriage 110 that carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5 and moves over the recording paper PP; and a carriage transport motor 91 for moving the carriage 110. The ultraviolet irradiation unit 5 is characterized by comprising a substrate 51, an ultraviolet light source E that is provided on the substrate 51 and emits ultraviolet light whose radiant flux characteristics change depending on the temperature, and a temperature detection integrated circuit 7 that is an integrated circuit that detects the temperature within the ultraviolet irradiation unit 5 and outputs a digital temperature detection signal DT based on the detected temperature.

[0157] According to Supplementary Note 2-1, the temperature detection integrated circuit 7 detects the temperature inside the ultraviolet irradiation unit 5, and therefore it is possible to determine whether the ultraviolet light source E needs to be stopped or to adjust the light emission intensity of the ultraviolet light source E based on the detected temperature inside the ultraviolet irradiation unit 5. Furthermore, according to Supplementary Note 2-1, the temperature detection integrated circuit 7 outputs the temperature detection signal DT, which is a digital signal, and therefore it is possible to reduce the possibility of noise being superimposed on the temperature detection signal DT output from the temperature detection integrated circuit 7, compared to an embodiment in which the output from the temperature detection integrated circuit 7 is an analog signal.

[0158] <<Appendix 2-2>> The inkjet printer 1 according to Appendix 2-2 is the inkjet printer 1 according to Appendix 2-1, characterized in that the radiant flux RE1 of ultraviolet light emitted from the ultraviolet light source E at temperature TE1 is greater than the radiant flux RE2 of ultraviolet light emitted from the ultraviolet light source E at temperature TE2 higher than temperature TE1.

[0159] <<Appendix 2-3>> The inkjet printer 1 according to Appendix 2-3 is the inkjet printer 1 according to Appendix 2-1 or 2-2, characterized in that the temperature detection integrated circuit 7 comprises a semiconductor temperature sensor 71 that detects temperature and outputs a sensor output signal VT, which is an analog signal indicating the detection result, and a signal conversion circuit 72 that converts the sensor output signal VT output by the semiconductor temperature sensor 71 into a temperature detection signal DT, which is a digital signal.

[0160] According to Supplementary Note 2-3, since the temperature detection integrated circuit 7 outputs the temperature detection signal DT, which is a digital signal, it is possible to reduce the possibility of noise being superimposed on the temperature detection signal DT output from the temperature detection integrated circuit 7, compared to a configuration in which the output from the temperature detection integrated circuit 7 is an analog signal.

[0161] <<Appendix 2-4>> The inkjet printer 1 according to Appendix 2-4 is the inkjet printer 1 according to Appendix 2-1 to Appendix 2-3, characterized in that it is equipped with a control unit 2 that controls the emission of ultraviolet light from the ultraviolet light source E based on a temperature detection signal DT, which is a digital signal output from a temperature detection integrated circuit 7.

[0162] According to Supplementary Note 2-4, the emission of ultraviolet light from the ultraviolet light source E is controlled based on the temperature inside the ultraviolet irradiation unit 5, making it possible to irradiate the ink on the recording paper PP with ultraviolet light of an appropriate intensity, thereby improving the print quality of the inkjet printer 1 compared to a configuration in which the ultraviolet light intensity is not adjusted. Additionally, according to Supplementary Note 2-4, it is possible to prevent the ultraviolet light source E from emitting ultraviolet light of an inappropriate intensity, making it possible to prevent a decrease in print quality of the inkjet printer 1 that would otherwise be caused by irradiating the recording paper PP with ultraviolet light of an inappropriate intensity.

[0163] <<Appendix 2-5>> The inkjet printer 1 according to Appendix 2-5 is the inkjet printer 1 according to Appendix 2-1 to Appendix 2-4, characterized in that the ultraviolet light source E comprises a light-emitting section 81 that emits ultraviolet light and a lens section 82 that seals the light-emitting section 81, and the lens section 82 is treated to be water-repellent.

[0164] According to Supplementary Note 2-5, it is possible to prevent the illuminance of the ultraviolet irradiation unit 5 from decreasing due to ink adhering to the lens portion 82.

[0165] <<Appendix 2-6>> The inkjet printer 1 according to Appendix 2-6 is the inkjet printer 1 according to Appendix 2-1 to Appendix 2-5, characterized in that the ultraviolet light source E comprises a light-emitting section 81 that emits ultraviolet light and a lens section 82 that seals the light-emitting section 81, and the lens section 82 is formed from silicone.

[0166] According to Supplementary Note 2-6, since silicone is water-repellent, it is possible to prevent the illuminance of the ultraviolet irradiation unit 5 from decreasing due to ink adhering to the lens portion 82.

[0167] <<Appendix 2-7>> The inkjet printer 1 according to Appendix 2-7 is the inkjet printer 1 according to Appendix 2-1 to Appendix 2-5, characterized in that the ultraviolet light source E comprises a light-emitting section 81 that emits ultraviolet light and a lens section 82 that seals the light-emitting section 81, the lens section 82 being formed from resin, and the ultraviolet irradiation unit 5 is provided between the ultraviolet light source E and the recording paper PP and comprises a cover plate 502 that transmits ultraviolet light.

[0168] According to Appendix 2-7, the cover plate 502 prevents ink from adhering to the ultraviolet light source E, thereby preventing a decrease in illuminance of the ultraviolet irradiation unit 5 due to ink adhering to the lens portion 82.

[0169] <<Appendix 2-8>> The inkjet printer 1 according to Supplementary Note 2-8 is the inkjet printer 1 according to Supplementary Notes 2-1 to 2-7, and is characterized in that the ultraviolet irradiation unit 5 includes a substrate 51, an ultraviolet light source E, and a housing 50 for housing the temperature detection integrated circuit 7.

[0170] <<Supplementary Note 2-9>> The inkjet printer 1 according to Supplementary Note 2-9 is the inkjet printer 1 according to Supplementary Notes 2-1 to 2-8, and is characterized in that the wiring 514 for electrically connecting the ultraviolet light source E to the substrate 51 is plated with gold 54.

[0171] According to Supplementary Note 2-9, the gold plating 54 enables the reduction of the resistance of the wiring 514, and enables the stabilization of the intensity of the ultraviolet light emitted from the ultraviolet light source E based on a stable power supply to the ultraviolet light source E.

[0172] <<Supplementary Note 2-10>> The inkjet printer 1 according to Supplementary Note 2-10 is the inkjet printer 1 according to Supplementary Notes 2-1 to 2-9, and is characterized in that the ultraviolet light source E includes a light emitting part 81 that emits ultraviolet light, a lens part 82 that seals the light emitting part 81, and a package part 83 that protects the light emitting part 81, and the package part 83 is formed of ceramic.

[0173] According to Supplementary Note 2-10, by adopting the ceramic package part 83, it is possible to suppress the deterioration of the package part 83 caused by ozone generated by the reaction of ultraviolet light with oxygen in the air as compared with the mode in which the package part 83 is formed of resin.

[0174] <<E.3. Supplementary Note 3>> Hereinafter, the inkjet printer 1 according to Supplementary Note 3 will be described.

[0175] <<Supplementary Note 3-1>> The inkjet printer 1 according to Appendix 3-1 comprises a liquid ejection unit 3 that ejects ink that hardens when exposed to ultraviolet light onto recording paper PP; an ultraviolet irradiation unit 5C that irradiates ultraviolet light onto the ink ejected onto the recording paper PP; a carriage 110 that mounts the liquid ejection unit 3 and the ultraviolet irradiation unit 5C side by side in the Y1 direction and moves above the recording paper PP in the Y1 direction; and a carriage transport motor 91 for moving the carriage 110. The ultraviolet irradiation unit 5C comprises an ultraviolet light source E that emits ultraviolet light, a wall surface 601B located between the ultraviolet light source E and the liquid ejection unit 3, and a wall surface 602 located on the opposite side of the ultraviolet light source E from the wall surface 601B, and the light absorptance of the wall surface 602 is higher than that of the wall surface 601B. In addition, in Supplementary Note 3, the wall surface 601B is an example of a "first wall surface," the wall surface 602 is an example of a "second wall surface," and the Y1 direction is an example of a "first direction."

[0176] According to Supplementary Note 3-1, the light absorptance of wall surface 602 is higher than that of wall surface 601B, and therefore, compared to an embodiment in which the light absorptance of wall surface 602 is lower than that of wall surface 601B, it is possible to keep the illuminance of ultraviolet light reaching the liquid ejection unit 3 low. Therefore, according to Supplementary Note 3-1, it is possible to suppress hardening of ink in the liquid ejection unit 3 and reduce the occurrence of abnormal ink ejection in the liquid ejection unit 3.

[0177] <<Appendix 3-2>> The inkjet printer 1 according to Supplementary Note 3-2 is the inkjet printer 1 according to Supplementary Note 3-1, characterized in that the wall surface 601B is a mirrored surface and the wall surface 602 is not a mirrored surface.

[0178] According to Supplementary Note 3-2, it is possible to keep the illuminance of ultraviolet light reaching the liquid discharge unit 3 low compared to an embodiment in which the wall surface 602 is a mirror surface.

[0179] <<Appendix 3-3>> The inkjet printer 1 according to Appendix 3-3 is the inkjet printer 1 according to Appendix 3-1 or Appendix 3-2, characterized in that the ultraviolet light source E comprises a light-emitting section 81 that emits ultraviolet light and a lens section 82 that seals the light-emitting section 81, and the height of the lens section 82 is greater than the diameter of the lens section 82.

[0180] According to Supplementary Note 3-3, the directionality of the ultraviolet light emitted from the ultraviolet light source E can be increased compared to an embodiment in which the height of the lens portion 82 is equal to or less than the diameter of the lens portion 82. Therefore, according to Supplementary Note 3-3, it is possible to keep the illuminance of the ultraviolet light reaching the liquid discharge unit 3 low.

[0181] <<Appendix 3-4>> The inkjet printer 1 according to Appendix 3-4 is the inkjet printer 1 according to Appendix 3-1 to Appendix 3-3, characterized in that the liquid ejection unit 3 ejects ink in the Z1 direction, which intersects with the Y1 direction, and the wall surface 601B is arranged so that when the distance in the Z1 direction from the substrate 51 on which the ultraviolet light source E is provided is a distance dZ1, the distance dY1 between the wall surface 601B in the Y1 direction and the liquid ejection unit 3 is longer than the distance dY2 between the wall surface 601B in the Y1 direction and the liquid ejection unit 3 when the distance in the Z1 direction from the substrate 51 is a distance dZ2 that is longer than the distance dZ1. In Supplementary Note 3, the distance dZ1 is an example of a "first distance," the distance dZ2 is an example of a "second distance," and the Z1 direction is an example of a "second direction."

[0182] According to Appendix 3-4, since the wall surface 601B is arranged to expand in the Y1 direction as it moves toward the Z1 direction, the amount of ultraviolet light irradiated from the ultraviolet irradiation unit 5C to the recording paper PP can be increased compared to an embodiment in which the wall surface 601B is arranged not to expand in the Y1 direction.

[0183] <<Appendix 3-5>> The inkjet printer 1 according to Supplementary Note 3-5 is the inkjet printer 1 according to Supplementary Note 3-1 to Supplementary Note 3-4, characterized in that when the ultraviolet irradiation unit 5C is viewed in cross section in a direction perpendicular to the Y1 and Z1 directions, the angle between the extension direction of the wall surface 601B and the Z1 direction is between 0 and 30 degrees. In other words, the inkjet printer 1 according to Supplementary Note 3-5 is the inkjet printer 1 according to Supplementary Note 3-1 to Supplementary Note 3-4, characterized in that the angle between the normal direction of the wall surface 601B and the Z1 direction is between 60 and 90 degrees.

[0184] According to Appendix 3-5, the amount of ultraviolet light irradiated from the ultraviolet irradiation unit 5C to the recording paper PP can be increased compared to when the angle between the extension direction of the wall surface 601B and the Z1 direction is less than 0 degrees or greater than 30 degrees.

[0185] <<Appendix 3-6>> The inkjet printer 1 according to Appendix 3-6 is the inkjet printer 1 according to Appendix 3-1 to Appendix 3-5, characterized in that the ultraviolet irradiation unit 5C is provided between the ultraviolet light source E and the recording paper PP and has a cover plate 502 that transmits ultraviolet light.

[0186] According to Supplementary Note 3-6, the cover plate 502 prevents ink from adhering to the ultraviolet light source E, thereby preventing a decrease in illuminance of the ultraviolet irradiation unit 5C due to ink adhering to the lens portion 82.

[0187] <<Appendix 3-7>> The inkjet printer 1 according to Supplementary Note 3-7 is the inkjet printer 1 according to Supplementary Note 3-6, characterized in that the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5C.

[0188] According to Supplementary Note 3-7, when ink adheres to the cover plate 502 and the ink hardens, etc., only the cover plate 502 can be replaced without removing the ultraviolet irradiation unit 5C. Therefore, compared with the aspect where the cover plate 502 cannot be replaced, the maintainability of the ultraviolet irradiation unit 5C is improved.

[0189] <<E.4. Supplementary Note 4>> Hereinafter, the inkjet printer 1 according to Supplementary Note 4 will be described.

[0190] <<Supplementary Note 4-1>> The inkjet printer 1 according to Supplementary Note 4-1 includes a liquid ejection unit 3 that ejects ink that cures by ultraviolet irradiation onto the recording paper PP, an ultraviolet irradiation unit 5B that irradiates ultraviolet rays onto the ink ejected onto the recording paper PP, a carriage 110 that mounts the liquid ejection unit 3 and the ultraviolet irradiation unit 5B so as to be arranged in the Y1 direction and moves on the recording paper PP in the Y1 direction, and a carriage conveyance motor 91 for moving the carriage 110. The distance between the ultraviolet irradiation unit 5B and the recording paper PP is 1 mm or more and 15 mm or less. The ultraviolet irradiation unit 5B includes an ultraviolet light source E that emits ultraviolet rays in the Z1 direction intersecting the Y1 direction, and a wall surface 601B that reflects at least a part of the ultraviolet rays emitted from the ultraviolet light source E. When the ultraviolet irradiation unit 5B is viewed in cross-section in a direction perpendicular to the Y1 direction and the Z1 direction, the angle formed by the extending direction of the wall surface 601B and the Z1 direction is 5 degrees or more and 15 degrees or less. In Supplementary Note 4, the wall surface 601B is an example of a "reflective surface", the Y1 direction is an example of a "first direction", and the Z1 direction is an example of a "second direction".

[0191] According to Supplementary Note 4-1, the angle between the extension direction of wall surface 601B and the Z1 direction is 5 degrees or more and 15 degrees or less, so the efficiency of irradiation of ultraviolet light from ultraviolet irradiation unit 5B onto recording paper PP can be increased compared to when the angle between the extension direction of wall surface 601B and the Z1 direction is less than 5 degrees. Also, according to Supplementary Note 4-1, the angle between the extension direction of wall surface 601B and the Z1 direction is 5 degrees or more and 15 degrees or less, so the maximum illuminance of ultraviolet light from ultraviolet irradiation unit 5B onto recording paper PP can be increased compared to when the angle between the extension direction of wall surface 601B and the Z1 direction is greater than 15 degrees. In other words, according to Supplementary Note 4-1, it is possible to both increase the maximum illuminance of ultraviolet light from ultraviolet irradiation unit 5B onto recording paper PP and increase the efficiency of irradiation of ultraviolet light from ultraviolet irradiation unit 5B onto recording paper PP.

[0192] <<Appendix 4-2>> The inkjet printer 1 according to Appendix 4-2 is the inkjet printer 1 according to Appendix 4-1, characterized in that when the ultraviolet irradiation unit 5B is viewed in cross section in a direction perpendicular to the Y1 direction and the Z1 direction, the angle between the extension direction of the wall surface 601B and the Z1 direction is greater than or equal to 5 degrees and less than or equal to 10 degrees.

[0193] According to Supplementary Note 4-2, it is possible to increase the maximum illuminance of ultraviolet light from the ultraviolet irradiation unit 5B onto the recording paper PP and to increase the irradiation efficiency of ultraviolet light from the ultraviolet irradiation unit 5B onto the recording paper PP.

[0194] <<Appendix 4-3>> The inkjet printer 1 according to Appendix 4-3 is the inkjet printer 1 according to Appendix 4-1 or Appendix 4-2, characterized in that the ultraviolet light source E comprises a light-emitting section 81 that emits ultraviolet light and a lens section 82 that seals the light-emitting section 81, and the height of the lens section 82 is greater than the diameter of the lens section 82.

[0195] According to Supplementary Note 4-3, the directivity of the ultraviolet light emitted from the ultraviolet light source E can be increased compared to an embodiment in which the height of the lens portion 82 is equal to or smaller than the diameter of the lens portion 82.

[0196] <<Appendix 4-4>> The inkjet printer 1 according to Appendix 4-4 is the inkjet printer 1 according to Appendix 4-1 to Appendix 4-3, characterized in that it is equipped with rubber parts, and the wavelength of the ultraviolet light emitted from the ultraviolet light source E is 250 nm or more and 410 nm or less. In addition, in Appendix 4, rubber parts are an example of "specific parts."

[0197] According to Supplementary Note 4-4, compared to the case where ultraviolet light having a wavelength of 100 nm or more and 230 nm or less is emitted from the ultraviolet light source E, it is possible to reduce the possibility that the ultraviolet light emitted from the ultraviolet light source E will react with oxygen in the air to generate ozone. Therefore, according to Supplementary Note 4-4, it is possible to suppress deterioration of rubber parts.

[0198] <<Appendix 4-5>> The inkjet printer 1 according to Appendix 4-5 is the inkjet printer 1 according to Appendix 4-1 to Appendix 4-4, characterized in that the ultraviolet irradiation unit 5B is provided between the ultraviolet light source E and the recording paper PP and has a cover plate 502 that transmits ultraviolet light.

[0199] According to Appendix 4-5, the cover plate 502 prevents ink from adhering to the ultraviolet light source E, thereby preventing a decrease in illuminance of the ultraviolet irradiation unit 5B due to ink adhering to the ultraviolet light source E.

[0200] <<Appendix 4-6>> The inkjet printer 1 according to Supplementary Note 4-6 is the inkjet printer 1 according to Supplementary Note 4-5, characterized in that the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5B.

[0201] According to Supplementary Note 4-6, since only the cover plate 502 can be replaced without removing the ultraviolet irradiation unit 5B, the maintainability of the ultraviolet irradiation unit 5B is improved as compared with the aspect where the cover plate 502 is not replaceable.

[0202] <<E.5. Supplementary Note 5>> Hereinafter, the inkjet printer 1 according to Supplementary Note 5 will be described.

[0203] <<Supplementary Note 5-1>> The inkjet printer 1 according to Supplementary Note 5-1 includes a liquid discharge unit 3 that discharges ink that cures by irradiation with ultraviolet light onto a recording paper PP, an ultraviolet irradiation unit 5 that irradiates the ink discharged onto the recording paper PP with ultraviolet light, a carriage 110 that mounts the liquid discharge unit 3 and the ultraviolet irradiation unit 5 so as to be arranged in the Y1 direction and moves on the recording paper PP in the Y1 direction, and a carriage conveyance motor 91 for moving the carriage 110. The ultraviolet irradiation unit 5 includes a plurality of ultraviolet light sources E that emit ultraviolet light toward the Z1 direction intersecting the Y1 direction, and one of the plurality of ultraviolet light sources E includes a light emitting portion 81 that emits ultraviolet light and a lens portion 82 that seals the light emitting portion 81. The lens portion 82 includes a cylindrical base portion 821 and a hemispherical tip portion 822 connected to the base portion 821 in the Z1 direction, and the height dEZ of the lens portion 82 in the Z1 direction is longer than the width dEY that is the diameter of the base portion 821. In Supplementary Note 5, one ultraviolet light source E is an example of the "first ultraviolet light source", the Y1 direction is an example of the "first direction", and the Z1 direction is an example of the "second direction".

[0204] According to Supplementary Note 5-1, it is possible to increase the directivity of the ultraviolet light emitted from one ultraviolet light source E, compared to an embodiment in which the height dEZ of the lens portion 82 in the Z1 direction is equal to or less than the diameter of the base portion 821. Therefore, according to Supplementary Note 5-1, it is possible to improve the irradiation efficiency of ultraviolet light from the ultraviolet irradiation unit 5, and also reduce the possibility that the ultraviolet light emitted from the ultraviolet irradiation unit 5 will be reflected by the recording paper PP and reach the liquid ejection unit 3, compared to an embodiment in which the height dEZ of the lens portion 82 in the Z1 direction is equal to or less than the diameter of the base portion 821.

[0205] <<Appendix 5-2>> The inkjet printer 1 according to Appendix 5-2 is the inkjet printer 1 according to Appendix 5-1, characterized in that the multiple ultraviolet light sources E are arranged in a line in the Y1 direction and the X1 direction that intersects the Y1 direction and the Z1 direction, and the distance dLY between two adjacent ultraviolet light sources E in the Y1 direction among the multiple ultraviolet light sources E is equal to or greater than the distance dLX between two adjacent ultraviolet light sources E in the X1 direction among the multiple ultraviolet light sources E. In Supplementary Note 5, the X1 direction is an example of the "third direction."

[0206] According to Supplementary Note 5-2, the distance dLX is equal to or less than the distance dLY, which reduces unevenness in the illuminance of the ultraviolet light source E in the X1 direction. Therefore, according to Supplementary Note 5-2, even when the carriage 110 carrying the ultraviolet irradiation unit 5 moves in the Y1 direction, it is possible for the ultraviolet irradiation unit 5 to irradiate the recording paper PP with ultraviolet light at a uniform intensity.

[0207] <<Appendix 5-3>> The inkjet printer 1 according to Appendix 5-3 is the inkjet printer 1 according to Appendix 5-1 or Appendix 5-2, characterized in that one ultraviolet light source E is adjacent to another ultraviolet light source E among the plurality of ultraviolet light sources E in the X1 direction, and the irradiation area on the recording paper PP of the ultraviolet light emitted from one ultraviolet light source E overlaps with the irradiation area on the recording paper PP of the ultraviolet light emitted from the other ultraviolet light sources E. In addition, in Supplementary Note 5, the other ultraviolet light source E is an example of a "second ultraviolet light source."

[0208] According to Supplementary Note 5-3, the irradiation range of ultraviolet light on the recording paper PP from one ultraviolet light source E and another ultraviolet light source E overlap, so that unevenness in the illuminance of the ultraviolet light source E in the X1 direction can be reduced.

[0209] <<Appendix 5-4>> The inkjet printer 1 according to Appendix 5-4 is the inkjet printer 1 according to Appendix 5-1 to Appendix 5-3, characterized in that it is equipped with rubber parts, and the wavelength of the ultraviolet light emitted from the ultraviolet light source E is 250 nm or more and 410 nm or less. In addition, in Appendix 5, rubber parts are an example of "specific parts."

[0210] According to Supplementary Note 5-4, compared to the case where ultraviolet light having a wavelength of 100 nm or more and 230 nm or less is emitted from the ultraviolet light source E, it is possible to reduce the possibility that the ultraviolet light emitted from the ultraviolet light source E will react with oxygen in the air to generate ozone. Therefore, according to Supplementary Note 5-4, it is possible to suppress deterioration of rubber parts.

[0211] <<Appendix 5-5>> The inkjet printer 1 according to Supplementary Note 5-5 is the inkjet printer 1 according to Supplementary Note 5-1 to Supplementary Note 5-4, characterized in that the ultraviolet irradiation unit 5 includes a heat sink 52 for cooling the multiple ultraviolet light sources E.

[0212] According to Supplementary Note 5-5, since the ultraviolet irradiation unit 5 includes the heat sink 52, the life of the plurality of ultraviolet light sources E can be extended compared to an embodiment in which the ultraviolet irradiation unit 5 does not include the heat sink 52. Therefore, according to Supplementary Note 5-5, it is possible to reduce the possibility of replacing all of the plurality of ultraviolet light sources E in order to prevent the irradiation intensity of ultraviolet light from the ultraviolet irradiation unit 5 from deviating from the desired intensity due to a malfunction of some of the ultraviolet light sources E among the plurality of ultraviolet light sources E.

[0213] <<Appendix 5-6>> The inkjet printer 1 according to Appendix 5-6 is the inkjet printer 1 according to Appendix 5-1 to Appendix 5-5, characterized in that the ultraviolet irradiation unit 5 is provided between the ultraviolet light source E and the recording paper PP and has a cover plate 502 that transmits ultraviolet light.

[0214] According to Appendix 5-6, the cover plate 502 can prevent ink from adhering to the ultraviolet light source E, thereby preventing a decrease in illuminance of the ultraviolet irradiation unit 5 due to ink adhering to the ultraviolet light source E.

[0215] <<Appendix 5-7>> The inkjet printer 1 according to Supplementary Note 5-7 is the inkjet printer 1 according to Supplementary Note 5-1 to Supplementary Note 5-6, characterized in that the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5.

[0216] According to Supplementary Note 5-7, since only the cover plate 502 can be replaced without removing the ultraviolet irradiation unit 5, the maintainability of the ultraviolet irradiation unit 5 is improved compared to an embodiment in which the cover plate 502 is not replaceable. [Explanation of symbols]

[0217] 1...inkjet printer, 2...control unit, 3...liquid ejection unit, 4...drive signal generation unit, 5...ultraviolet irradiation unit, 6...ultraviolet light source module, 7...temperature detection integrated circuit, 9...transport unit, 50...casing, 51...substrate, 52...heat sink, 53...grease, 54...gold plating, 61...wall portion, 62...wall portion, 71...semiconductor temperature sensor, 72...signal conversion circuit, 81...light emitting portion, 82...lens portion, 83...package portion, 84...connection wiring portion, 91...carriage transport motor, 92...medium transport motor, 95...platen, 110...carriage, 501...frame, 502...cover plate, 511...substrate, 512...insulating layer, 513...resist, 514...wiring, 601...wall surface, 602...wall surface, D...ejection portion, E...ultraviolet light source

Claims

1. a liquid ejection unit that ejects a liquid that hardens when irradiated with ultraviolet light onto a medium; an irradiation unit that irradiates the liquid ejected onto the medium with ultraviolet light; a carriage that carries the liquid ejection unit and the irradiation unit and moves over the medium; a motor for moving the carriage; Equipped with The irradiation unit comprises: A substrate; an ultraviolet light source that is provided on the substrate and emits ultraviolet light; Equipped with The substrate has an aluminum base. A liquid ejection device characterized by:

2. At least a portion of the heat generated in the ultraviolet light source is dissipated through the base material. The liquid ejection device according to claim 1 .

3. The surface area of ​​the base material is larger than the area of ​​the region of the substrate where the ultraviolet light source is provided. The liquid ejection device according to claim 1 .

4. An aluminum heat sink is attached to the substrate. The liquid ejection device according to claim 1 .

5. The ultraviolet light source is a light emitting diode that emits ultraviolet light. The liquid ejection device according to claim 1 .

6. The substrate is provided with a temperature sensor. The liquid ejection device according to claim 1 .

7. The substrate is provided with a signal conversion circuit that converts the output from the temperature sensor into a digital signal, the temperature sensor and the signal conversion circuit are packaged as an integrated circuit; 7. The liquid ejection device according to claim 6, wherein the liquid ejection device comprises: a nozzle;

8. the irradiation unit includes a housing including a cover plate that transmits ultraviolet light and a frame; The substrate and the ultraviolet light source are provided within the housing. The liquid ejection device according to claim 1 .

9. a liquid ejection unit that ejects a liquid that hardens when irradiated with ultraviolet light onto a medium; a carriage that carries the liquid ejection unit and moves over the medium; a motor for moving the carriage; The liquid ejection device includes: an ultraviolet irradiation device mounted on the carriage and configured to irradiate ultraviolet rays onto the liquid ejected onto the medium, A substrate; an ultraviolet light source that is provided on the substrate and emits ultraviolet light; Equipped with The substrate has an aluminum base. An ultraviolet irradiation device characterized by:

10. At least a portion of the heat generated in the ultraviolet light source is dissipated through the base material.

10. The ultraviolet irradiation device according to claim 9.

11. The surface area of ​​the base material is larger than the area of ​​the region of the substrate where the ultraviolet light source is provided.

10. The ultraviolet irradiation device according to claim 9.

12. An aluminum heat sink is attached to the substrate.

10. The ultraviolet irradiation device according to claim 9.

13. The ultraviolet light source is a light emitting diode that emits ultraviolet light.

10. The ultraviolet irradiation device according to claim 9.

14. The substrate is provided with a temperature sensor.

10. The ultraviolet irradiation device according to claim 9.

15. The substrate is provided with a signal conversion circuit that converts the output from the temperature sensor into a digital signal, the temperature sensor and the signal conversion circuit are packaged as an integrated circuit; 15. The ultraviolet irradiation device according to claim 14.

16. The device includes a housing including a cover plate that transmits ultraviolet light and a frame, The substrate and the ultraviolet light source are provided within the housing.

10. The ultraviolet irradiation device according to claim 9.

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